Coating with metal.



CHA .R,LES F. BURGESS, QF MADISON, WISGONSIN, ASSIGNOB T UNI'1ED STATES SHERARDIZING COMPANY, OE NEW CASTLE, PENNSYLVANIA, A CORE'OBATION or new JERSEY.

COATING WITH METAL.

No Drawing.

To all whom, it may concern:

Be it known that I, CHARLES F. BURGESS,

- a citizen of the United States, residing at hot galvanizin in granular formand consisting largely ofzinc, may be utilized in coating iron articles and the like to protect them from corrosion.

According totheflwell-known method of 5 the iron or steel. articles to be coated are ipp'ed in fused zinc, which is held in an ironrec'eptacle witlra layer of salammoniac floating. on its surface to serve as 1a flux. It known that the molten zinc dissolves ofi'soin'e or the iron of the article under treatment, and. also eats away the iron tank or receptacle by combining therewith.

. It is also. known that the combined zinc and ironsettle to.v the. bottom of the tank, and

' must .be taken out from time to time, other- 'wise the bath becomes'dirty anclwill not stay sufliciently liquid at the working temperature of the flux. material thus removed market at a relatively low price as from the hot galvanizing bath analyzes about 3% to 7% iron, and 97% to 93% zinc, with. lead and other impurities, and is sold (pin the;

oss.

'The material is somewhat harder than zinc,

and relatively tough and strong.

According to the preferred embodiment of-the present invention, galvanizers dross is utilized as the basis for the production,

in novel manner, of an alloy or composition of matter containing zinc and iron, and

having extreme brittleness, and having also other special characteristics which render it valuable for use in the arts, and more particularly in connection with a process devised by'me, and hereinafter described in detail.

To make up the alloy or composition, zinc rd'ross of ordinary commercial purity s crushed or broken into lumps and is then placed in a rotar iron drum, together with gr a quantity of re, atively pure iron, such as 'wrought iron, or

electrolytic iron, in the form of chunks or small pieces. This charge of dross and iron is'then heated to red heat, (about 850 degrees Fahri), with continued rotation of the drum, I have found. that at this temperature, which is well below the melting point of the dross, the iron and dross appear to combine,'and

Specification of. Letters Patent.'

Patented- Jan. 16,1912.

Application filed June 1.6, 1910.. Serial No. 567,244.

the iron, as such, disappears. By adding the iron in suitable proportions, all of the iron may be caused to combine with the dross, yielding an alloy of about the composition ,FeZn This alloy has properties differing in many ways from those of its "constituent metals. It is exceedingly brittle, and the rotation of the drum causes the lumps or particles of alloy to grind on one another, thereby reducing substantially the entire charge to a granular condition. 'Thealloy, when thus reduced to granular condition, can be heated to a temperature in the neighborhood of 1300 degrees Fahr. without fusion and without sintering of the particles into a coherent mass, Inthis respect, it is quite different from pulverized zinc, which fuses at about 740 degrees Fahr. When in granular condition, the alloy FeZn is light gray, and the individual .granules or particles appear to be regularly crystalline in structure. The alloy, when in granular state, is in condition for use according to a method described and claimed in my copending. application Serial No. 552,940, filed Apr1l'2, 1910,said method in cluding heat treatment of an iron article while in coutact with a brittle zinc alloy, with the result that the iron article takes on a protective coating. However, 1 have found that. under some circumstances it is best that the granular material should contain difiusmgjthrough the interstices of the en-- .tire granular. mass and collecting on the ains of FeZn thereby raising the zinc content of the mass without destroying its brittleness, and Without changing it from its granular condition. This material" so produced does not oxidize readily, and will not explode.

may vary through wide limits, but an additionof 5% is suitable. .When using this granular material to produce a protective The exact amount of zinc added to enrich the originalbrittle alloy until thev take on or ornamental coating on iron or steel articles, the articles are first suitably cleaned by sand-blasting and pickling, or the like, and are then put in the rotary drum with the granular material, and there heated a protective coating or covering. The temperature and duration of heating can be suitably regulated to governthe thickness of the coating. Heating for two hours and to a maximum temperature of about 850' degrees Fahngwes good results when the granular material contains about 5% zinc over and above that chemically combined as Fezn v By repeated use of the granular'materlal, some of its zinccontent may be used up by combining with iron from articles to be coated, or in other ways,'making desirable the replenishment'of the granular mass with zinc. This may be done without interrupting the normal operation merely by adding pieces of scr p zinc or lumps when the charge ofiron articles is being added to the drum. Durin the subsequent rotation of the drum, the high temperature and the grinding action of the charge eifecsmooth the surface of composition or richness,

'igranular the size of the granules t-ively vaporize-and wear away the zinc lumps or scraps and distribute the material uniformly-throughout the granular mass where it collects on the exposed surfaces -of the grains, bringing'the mass to the desired but leaving it still The size of the particles is not uniform throughout the mass,-and although most of the mass is fine enough to be passed through a 40- coarse to pass This variation in is of importance. into intimate conthe larger particles scouring agents to thejiron and of. the

ma granular condition.

through a GO-mesh sieve.

The fine particles come tact with the iron While serve, as grinding or coating while the coating is being produced.

"with respect to iron,

from corrosion.

whlte in color, and has 1e granular mass is not readily inflamma: ble, andcan be'exposed to the air even at red .heat without exploding.

, The coating producedon the iron articles as herein described is very dense, and silver v a chemical composition of about FeZn throughout the reater part of its thi'clmess. It is hard an dense in structure, and has an electrical potential with respect to electrolytes, slight y above that o-f pure .iron. ,Being electro ositive What I claim as new, and desire'to secure by Letters flopiee 91' thisfflate'nt may be obtained for five cents each, by 4 Washington, D. 0.

of zinc dross it protects. t eiron.

Patent of the United States is -1. The process of coating a metal" article with -a protective and adherent covering, which consists in applying to said article a material comprising a granular zinc-iron alloy enriched with uncombin .d zinc, and heating said article until it takes on a protective coating.

2. The process of coating an iron article with a protective layer, which consists in heating the article at about-dull red while in contact with granular FeZn enriched with additional zinc.

3. The method which ing a granular body consisting largely of zinc and iron, heat-ing said body in contact wvith iron articles'to form a protective coat-' tainlng materially more zinc thanwould be represented by the symbol FeZn 5. The method which consists in producing a body of granular material consisting largely of a zinc-iron alloy, applying said granular material to aniron' surface, submitting the same to'the action of .heat to periodically enriching said granular material by heat 6. The method of tive coating on an iron surface'whi'ch consists in applying thereto a granular material consisting mainly of zinc and iron, and heating said surface to about red heat, said granular material having been produced'by tumbling zlnc-dross at'about red heat in the presence of uncombined zinc."

7. The method which consists in producproducing a protec-' consists in produc-,

treatment in the presence of additional zinc.

ing a subdivided material containingzinc alloyed with iron, applying said material to an iron surface, heating said surface until a protective coating forms thereon, riodically enriching said subdivided material by heating in the presence of additional zinc.

In witness whereof, I have hereunto set my hand -this seventh day of June, A.D. 1910.

v QHARLES rf'BUneEss. Withesses: i

- VROMAN Mason,

- IRMA WISWALL.

addressing the Commissioner of Patents,

and pe- 

